.\" $OpenBSD: X509_VERIFY_PARAM_new.3,v 1.5 2023/05/24 09:57:50 tb Exp $
.\"
.\" Copyright (c) 2018, 2021 Ingo Schwarze <schwarze@openbsd.org>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd $Mdocdate: May 24 2023 $
.Dt X509_VERIFY_PARAM_NEW 3
.Os
.Sh NAME
.Nm X509_VERIFY_PARAM_new ,
.Nm X509_VERIFY_PARAM_inherit ,
.Nm X509_VERIFY_PARAM_set1 ,
.Nm X509_VERIFY_PARAM_free ,
.Nm X509_VERIFY_PARAM_add0_table ,
.Nm X509_VERIFY_PARAM_lookup ,
.Nm X509_VERIFY_PARAM_get_count ,
.Nm X509_VERIFY_PARAM_get0 ,
.Nm X509_VERIFY_PARAM_table_cleanup
.\" The following constants defined in the public header <openssl/x509_vfy.h>
.\" are intentionally undocumented because X509_VERIFY_PARAM is an opaque
.\" struct and LibreSSL provides neither X509_VERIFY_PARAM_set_inh_flags(3)
.\" nor X509_VERIFY_PARAM_get_inh_flags(3):
.\" X509_VP_FLAG_DEFAULT
.\" X509_VP_FLAG_OVERWRITE
.\" X509_VP_FLAG_RESET_FLAGS
.\" X509_VP_FLAG_LOCKED
.\" X509_VP_FLAG_ONCE
.Nd X509 verification parameter objects
.Sh SYNOPSIS
.In openssl/x509_vfy.h
.Ft X509_VERIFY_PARAM *
.Fo X509_VERIFY_PARAM_new
.Fa void
.Fc
.Ft int
.Fo X509_VERIFY_PARAM_inherit
.Fa "X509_VERIFY_PARAM *destination"
.Fa "const X509_VERIFY_PARAM *source"
.Fc
.Ft int
.Fo X509_VERIFY_PARAM_set1
.Fa "X509_VERIFY_PARAM *destination"
.Fa "const X509_VERIFY_PARAM *source"
.Fc
.Ft void
.Fo X509_VERIFY_PARAM_free
.Fa "X509_VERIFY_PARAM *param"
.Fc
.Ft int
.Fo X509_VERIFY_PARAM_add0_table
.Fa "X509_VERIFY_PARAM *param"
.Fc
.Ft const X509_VERIFY_PARAM *
.Fo X509_VERIFY_PARAM_lookup
.Fa "const char *name"
.Fc
.Ft int
.Fo X509_VERIFY_PARAM_get_count
.Fa void
.Fc
.Ft const X509_VERIFY_PARAM *
.Fo X509_VERIFY_PARAM_get0
.Fa "int id"
.Fc
.Ft void
.Fo X509_VERIFY_PARAM_table_cleanup
.Fa void
.Fc
.Sh DESCRIPTION
.Fn X509_VERIFY_PARAM_new
allocates and initializes an empty
.Vt X509_VERIFY_PARAM
object.
.Pp
.Fn X509_VERIFY_PARAM_inherit
copies some data from the
.Fa source
object to the
.Fa destination
object.
.Pp
The verification flags set with
.Xr X509_VERIFY_PARAM_set_flags 3
in the
.Fa source
object are always OR'ed into the verification flags of the
.Fa destination
object.
.Pp
Fields having their default value in the
.Fa source
object are not copied.
.Pp
By default, fields in the
.Fa destination
object already having a non-default value are not overwritten.
However, if at least one of the
.Fa source
or
.Fa destination
objects was created during a call to
.Xr X509_STORE_CTX_init 3
that did not have a
.Fa store
argument, and if that object was not previously used as the
.Fa destination
in an earlier call to
.Fn X509_VERIFY_PARAM_inherit ,
this restriction is waived and even non-default fields in the
.Fa destination
object get overwritten.
If fields overwritten in this way contain pointers to allocated memory,
that memory is freed.
.Pp
As far as permitted by the above rules, the following fields are copied:
.Bl -bullet -width 1n
.It
the verification purpose identifier set with
.Xr X509_VERIFY_PARAM_set_purpose 3
.It
the trust setting set with
.Xr X509_VERIFY_PARAM_set_trust 3
.It
the verification time set with
.Xr X509_VERIFY_PARAM_set_time 3 ;
in this case, the only condition is that
.Dv X509_V_FLAG_USE_CHECK_TIME
is not set in the
.Fa destination
object, whereas the time value in the
.Fa destination
object is not inspected before overwriting it
.It
the acceptable policy set with
.Xr X509_VERIFY_PARAM_set1_policies 3
.It
the maximum verification depth set with
.Xr X509_VERIFY_PARAM_set_depth 3
.It
flags that were set with
.Xr X509_VERIFY_PARAM_set_hostflags 3
.It
the list of expected DNS hostnames built with
.Xr X509_VERIFY_PARAM_set1_host 3
and
.Xr X509_VERIFY_PARAM_add1_host 3
.It
the expected RFC 822 email address set with
.Xr X509_VERIFY_PARAM_set1_email 3
.It
the expected IP address set with
.Xr X509_VERIFY_PARAM_set1_ip 3
or
.Xr X509_VERIFY_PARAM_set1_ip_asc 3
.El
.Pp
Some data that may be contained in the
.Fa source
object is never copied, for example the subject name of the peer
certificate that can be retrieved with
.Xr X509_VERIFY_PARAM_get0_peername 3 .
.Pp
If
.Fa source
is a
.Dv NULL
pointer, the function has no effect but returns successfully.
.Pp
.Fn X509_VERIFY_PARAM_set1
is identical to
.Fn X509_VERIFY_PARAM_inherit
except that fields in the
.Fa destination
object are overwritten even if they do not match their default values.
Still, fields having their default value in the
.Fa source
object are not copied.
.Pp
If
.Fn X509_VERIFY_PARAM_inherit
or
.Fn X509_VERIFY_PARAM_set1
fail, partial copying may have occurred, so all data in the
.Fa destination
object should be regarded as invalid.
.Pp
.Fn X509_VERIFY_PARAM_inherit
is used internally by
.Xr X509_STORE_CTX_init 3
and by
.Xr X509_STORE_CTX_set_default 3 ,
and
.Fn X509_VERIFY_PARAM_set1
is used internally by
.Xr X509_STORE_set1_param 3 .
.Pp
.Fn X509_VERIFY_PARAM_free
clears all data contained in
.Fa param
and releases all memory used by it.
If
.Fa param
is a
.Dv NULL
pointer, no action occurs.
.Pp
.Fn X509_VERIFY_PARAM_add0_table
adds
.Fa param
to a static list of
.Vt X509_VERIFY_PARAM
objects maintained by the library.
This function is extremely dangerous because contrary to the name
of the function, if the list already contains an object that happens
to have the same name, that old object is not only silently removed
from the list, but also silently freed, which may silently invalidate
various pointers existing elsewhere in the program.
.Pp
.Fn X509_VERIFY_PARAM_lookup
searches this list for an object of the given
.Fa name .
If no match is found, the predefined objects built-in to the library
are also inspected.
.Pp
.Fn X509_VERIFY_PARAM_get_count
returns the sum of the number of objects on this list and the number
of predefined objects built-in to the library.
Note that this is not necessarily the total number of
.Vt X509_VERIFY_PARAM
objects existing in the program because there may be additional such
objects that were never added to the list.
.Pp
.Fn X509_VERIFY_PARAM_get0
accesses predefined and user-defined objects using
.Fa id
as an index, useful for looping over objects without knowing their names.
An argument less than the number of predefined objects selects
one of the predefined objects; a higher argument selects an object
from the list.
.Pp
.Fn X509_VERIFY_PARAM_table_cleanup
deletes all objects from this list.
It is extremely dangerous because it also invalidates all data that
was contained in all objects that were on the list and because it
frees all these objects, which may invalidate various pointers
existing elsewhere in the program.
.Sh RETURN VALUES
.Fn X509_VERIFY_PARAM_new
returns a pointer to the new object, or
.Dv NULL
on allocation failure.
.Pp
.Fn X509_VERIFY_PARAM_inherit ,
.Fn X509_VERIFY_PARAM_set1 ,
and
.Fn X509_VERIFY_PARAM_add0_table
return 1 for success or 0 for failure.
.Pp
.Fn X509_VERIFY_PARAM_lookup
and
.Fn X509_VERIFY_PARAM_get0
return a pointer to an existing built-in or user-defined object, or
.Dv NULL
if no object with the given
.Fa name
is found, or if
.Fa id
is at least
.Fn X509_VERIFY_PARAM_get_count .
.Pp
.Fn X509_VERIFY_PARAM_get_count
returns a number of objects.
.Sh SEE ALSO
.Xr SSL_set1_param 3 ,
.Xr X509_STORE_CTX_set0_param 3 ,
.Xr X509_STORE_set1_param 3 ,
.Xr X509_verify_cert 3 ,
.Xr X509_VERIFY_PARAM_set_flags 3
.Sh HISTORY
.Fn X509_VERIFY_PARAM_new ,
.Fn X509_VERIFY_PARAM_inherit ,
.Fn X509_VERIFY_PARAM_set1 ,
.Fn X509_VERIFY_PARAM_free ,
.Fn X509_VERIFY_PARAM_add0_table ,
.Fn X509_VERIFY_PARAM_lookup ,
and
.Fn X509_VERIFY_PARAM_table_cleanup
first appeared in OpenSSL 0.9.8 and have been available since
.Ox 4.5 .
.Pp
.Fn X509_VERIFY_PARAM_get_count
and
.Fn X509_VERIFY_PARAM_get0
first appeared in OpenSSL 1.0.2 and have been available since
.Ox 6.3 .
